In most independent suspensions a change of ride height is accompanied by a change of track because the wheels are attached to suspension arms which pivot, usually about their inboard end, as the body is raised or lowered. The wheels therefore move relative to the body in an arc rather than a straight line. If the vehicle is stationary when the height change is occurring, the friction between the wheels and the ground can prevent the wheels from slipping sideways and therefore prevent or hinder the change of height. This can result in the vehicle becoming stuck at a ride height which is different from the desired ride height. A lot of energy can then be expended as the system tries to overcome friction, especially if the ride height is increasing. Also, when the vehicle starts to move the ride height, and track, can change with much less resistance, and this can lead to a sudden height change which is uncomfortable or disconcerting for the driver.